• Journal of KIISE:Software and Applications
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• v.29 no.3
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• pp.192-201
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• 2002

Automated text classification is considered as an important method to manage and process a huge amount of documents in digital forms that are widespread and continuously increasing. Recently, text classification has been addressed with machine learning technologies such as k-nearest neighbor, decision tree, support vector machine and neural networks. However, only few investigations in text classification are studied on real problems but on well-organized text corpus, and do not show their usefulness. This paper proposes and analyzes text classification methods for a real application, email document classification task. First, we propose a combining method of multiple neural networks that improves the performance through the combinations with maximum and neural networks. Second, we present another strategy of combining multiple machine learning classifiers. Voting, Borda count and neural networks improve the overall classification performance. Experimental results show the usefulness of the proposed methods for a real application domain, yielding more than 90% precision rates.

• The Journal of the Korea Contents Association
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• v.10 no.12
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• pp.243-253
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• 2010

The competition for telecommunication-broadcasting bundle is under full steam. Even large mobile OS companies like Apple and Google are showing signs of moving into the telecom and broadcasting industry, and it is expected that competition for bundle will become even fiercer. In the light of this situation, this study will show which factors can heighten purchasing intention for bundle and lower expected-discounting rates, seeking its answer in the quality, satisfaction, and brand loyalty to core product. The results of the study show that the brand loyalty to core product affects the customer's purchasing intention positively while lowering expected-discounting rates. This conclusion suggests the importance of a marketing strategy that heightens satisfaction of existing customers who use a single item, which is just as important as strategies to induce switching behavior of the customers of other companies through competitive pricing. Also, the results suggest that rather than appeal to loyal customers through discounts, it is more effective to offer them different benefits or value.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.5
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• pp.119-126
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• 2018

Recently, the production of circulating fluidized bed combustion ash has been increased in thermal power plants. The addition of limestone for the desulfurizing effect of circulating fluidized bed boiler ash increases the content of CaO and $SO_3$ contained in ash, which is higher than the free fly ash in general fly ash. Unlike conventional fly ash, the circulating fluidized bed combustion ash has a high reactivity when it comes into contact with water due to its hydraulic properties and high free-CaO content. The aim of this study is to investigate the possibility of non-sintered binder by using self-cementing properties of circulating fluidized bed combustion ash. The mechanical and hydration characteristics were investigated according to the content of CFBC ash. In addition, the effects of gymsum type and content on the compressive strength and micro-structure of non-sintered binder pastes.

• Journal of Digital Convergence
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• v.15 no.1
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• pp.199-208
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• 2017

This study investigates the components and rating system of reliable technology credit information for a technology finance donor who is a consumer of the information and aims to create an effective and optimal technology credit appraisal system to enlarge technology finance supply. Firstly, we calculate the optimal TCAR which becomes the maximum AUROC through the combination of ratio change, verify the substitution possibility between TAR and CR through the existing CR and system gap simulation, and propose a rating system by which financial institutes can utilize the TCAR as a credit rating. As a result, 70% : 30% is the most suitable as the weighted combination ratio of credit rating : technology rating. As a result of this study, we confirmed the possibility that the technical credit rating information could be substituted by the credit rating or the technology appraisal rating. Furthermore, it also suggests that sophisticated risk management is possible through using technology credit rating that are combined with credit and technology appraisal rating.

• Elastomers and Composites
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• v.41 no.4
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• pp.231-237
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• 2006

An enzyme electrode bound by butyl rubber was newly constructed for the determination of hydrogen peroxide and for the practical application as a biosensor. Then its electrochemical properties were investigated. It produced a hundreds-fold increased signal compared to the plant or animal tissue based biosensor studied previously and could be run at between $0.0{\sim}-1.00\;V$(vs. Ag/AgCl). The relationship between signal and electrode potential was linear in the experimental range of potential. It showed a detection limit of $3.0{\times}10^{-4}\;M$ and a very good linearity of Lineweaver-Burk plot giving the proof of a good enzyme immobilization. Especially, both the reproducibility of signal current due to its high sensitivity and mechanical stability presented a new possibility for the practical use of biosensor bound with butyl rubber.

• Membrane Journal
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• v.31 no.3
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• pp.184-199
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• 2021

As a branch of covalent organic frameworks (COF), covalent triazine frameworks (CTF) are inherently porous structures composed of networks of repeating hexagonal triazine rings fabricated via the ionothermal trimerization reaction. They also contain plenty of nitrogen functional groups that increase affinity for some chemicals while rejecting others. Because of their tunable properties, many researchers have synthesized and tested CTFs for gas and liquid separation processes. Various studies of novel CTFs, mixed CTF composites, and CTF membranes have experimented for gas adsorption/separation (e.g., CO₂, C₂H₂, H₂, etc.) and desalination. Some CTF studies have determined the limits and potentials through advanced computer simulations while subsequent experiments have tested CTFs for photocatalytic properties, suggesting recyclability for greater sustainability. In this review, the covalent triazine framework-based separation membrane is discussed.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.237-247
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• 2019

This study looks at common features between the two media to explore the deepening relationship within music and images in movies and finds at how they are combined each other and the resulting effects. Beyond the limitations of conventional viewpoints of music as video-dependent media, The is analyzed to focus on the deepening relationship between the two media. In the movie, music and video were combined by sharing the same attributes of 'repeating structure', which increases the transmission power to the film's subject and story, maximizes visual and auditory stimuli, and forms a sense of immersion. That is, video and music combined in equal positions have great influence to each other, thus representing for a positive consideration of the potential for establishing interdependent relationships.

• Environmental and Resource Economics Review
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• v.27 no.2
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• pp.215-231
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• 2018

It is expected that the korean power retail market will be reorganized someday. Thus, this study analyzes the changes in consumers' utility level when new companies enter the retail market and offer various bundled services. For the analysis, the utility function of the consumers was estimated using the conjoint choice method. The results of the analysis can be summarized in two-folds. First, consumer will still prefer KEPCO in electricity sales. Therefore, difficulties can be expected when new companies enter the power retail market. Second, consumers do not favor bundled services in the electricity market also. Bundled services would not provide as much as utility each service provide separately.

• The Journal of Bigdata
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• v.7 no.2
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• pp.75-90
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• 2022

Recently, complex and sophisticated analysis of transportation is required due to changes in the socioeconomic environment and the development of bigdata technology. Especially, the revision of 3 laws including PERSONAL INFORMATION PROTECTION ACT makes it possible to combine various types of mobility data. But strengthen personal information protection makes inefficiency in utilizing mobility bigdata. In this paper, we proposed the "Virtual fusion methdology via mobility bigdata" which is a methodology for indirect data fusion for various mobility bigdata such as mobile data and transportation card data, in order to resolve legal restrictions and enable various transportation analysis. And we also analyzed regional bus passenger in Seoul capital area and Cheongju city with aforementioned methodology for verification. This methdology could analyze behavioral pattern of passenger with the MCGM(Mobility Comprehensive Genetic Map), graph with position and time, making with mobile data. Consquently, using MCGM, which is a result for indirect data fusion, makes it possible to analyze various transportation problems.

• Review of Culture and Economy
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• v.20 no.1
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• pp.105-128
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• 2017

The purpose of this paper is to analyze the impact of distributors on the movie exhibition by distributor types. For the analysis, the concept 'screen elasticity of box office' is adopted. Using the weekly screening data of 94 hit movies released in Korea in 2014 and 2015, the panel analysis estimates the 'screen elasticity of box office' with the Hausman-Taylor estimator. The results show that the screen elasticity of box office is smaller for vertically integrated distributors(CJ E&M and Lotte Entertainment) and Hollywood distributors than the local distributors(Showbox and NEW) that do not own integrated cinemas. This means that exhibitors allocate a larger number of screens to vertically integrated distributors and Hollywood distributors. As the two distributor groups had higher market share during the period, the results imply that the screen elasticity is related to the market performance of distributors. Smaller screen elasticity of the vertically integrated distributors might be related not to the ownership to theaters but to higher market share of the distributors.